As a technique for outputting a large torque from a motor, a geared motor has been proposed in which an output member whose outer peripheral portion is formed with a spiral groove is provided between a first plate part and a second plate part of a frame and a motor pinion fixed to a rotation shaft is transmitted to a gear part of the output member (see Patent Literature 1). In the geared motor, the output member is rotatably supported between a bearing provided in the first plate part and the second plate part. A large opening part is provided in the first plate part and, when the geared motor is to be manufactured, the output member is passed through the opening part between the first plate part and the second plate part.